anacosmism

Something or someone that is not in its correct universe, dimension or cosmic location. Coined by Jennifer Diane Reitz to label errors in fantasy literature where people or things described are specific to Earth and ought not to exist in the fictional universe of the work.

These errors go beyond mere 'anatopism' (referring to something is in the wrong geographic location but at least on the correct planet). Also analogous to anachronism, where something is in the wrong time.

If a sci-fi novel set in the Andromeda galaxy used the months January to June, that would be an anacosmism because the Roman Empire and their calendar never existed in Andromeda.